Equation of state for hot hyperonic neutron star matter

Understand

The FSU2H equation-of-state model, originally developed to describe cold neutron star matter with hyperonic cores, is extended to finite temperature.

• Results are presented for a wide range of temperatures and lepton fractions, which cover the conditions met in protoneutron star matter, neutron star mergers and supernova explosions.
• It is found that the temperature effects on the thermodynamical observables and the composition of the neutron star core are stronger when the hyperonic degrees of freedom are considered.
• An evaluation of the temperature and density dependence of the thermal index leads to the observation that the so-called $\Gamma$ law, widely used in neutron star merger simulations, is not appropriate to reproduce the true thermal effects, specially when hyperons start to be abundant in the neutron star core.